Day 7: Bridge Repair

Megathread guidelines

  • Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
  • You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL

FAQ

  • iAvicenna@lemmy.world
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    2 days ago

    If you havent already done so, doing it in the form of “tree search”, the code completes in the blink of an eye (though on a high end cpu 11th Gen Intel® Core™ i7-11800H @ 2.30GHz). posted the code below

    • stevenviola
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      3 days ago

      Thanks! yup, I figured there would be a way. You’re right, much faster, on my machine with your code, this is the speed:

      $ time python3 day7.py 
      4555081946288
      227921760109726
      
      real    0m0.171s
      

      I’ll have to take a look to understand how that works to be better.

      • Acters@lemmy.world
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        2 days ago

        I posted my solution here and found my way to finish 30 milliseconds faster.(~100ms for his, and ~66 ms for mine) However, as I noted I stop prematurely sometimes. Which seems to work with my given input. but here is the one that makes sure it gets to the end of the list of integers:

        code
        def main(input_data):
            input_data = input_data.replace('\r', '')
            parsed_data = {int(line[0]): [int(i) for i in line[1].split()[::-1]] for line in [l.split(': ') for l in input_data.splitlines()]}
            part1 = 0
            part2 = 0
            for item in parsed_data.items():
                root, num_array = item
                part_1_branches = [set() for _ in range(len(num_array)+1)]
                part_2_branches = [set() for _ in range(len(num_array)+1)]
                part_1_branches[0].add(root)
                part_2_branches[0].add(root)
                for level,i in enumerate(num_array):
                    if len(part_1_branches[level]) == 0 and len(part_2_branches[level]) == 0:
                        break
        
                    for branch in part_1_branches[level]:
                        if level==len(num_array)-1:
                            if branch == i:
                                part1 += root
                                break
                        if branch % i == 0:
                            part_1_branches[level+1].add(branch//i)
                        if branch - i > 0:
                            part_1_branches[level+1].add(branch-i)
        
                    for branch in part_2_branches[level]:
                        if level==len(num_array)-1:
                            if (branch == i or str(branch) == str(i)):
                                part2 += root
                                break
                        if branch % i == 0:
                            part_2_branches[level+1].add(branch//i)
                        if branch - i > 0:
                            part_2_branches[level+1].add(branch-i)
                        if str(i) == str(branch)[-len(str(i)):]:
                            part_2_branches[level+1].add(int(str(branch)[:-len(str(i))].rjust(1,'0')))
            
            print("Part 1:", part1, "\nPart 2:", part2)
            return [part1, part2]
        
        if __name__ == "__main__":
            with open('input', 'r') as f:
                main(f.read())